From Electromechanical-to-Digital-to-Hippie fiber lamps and BEYOND at Optical Light Speed…

The telephone switching and signaling process has come a long way in since the days of the rotary electromechanical or the analogues line and trunk switches. 

The CAS/CCS and SS7 signaling techniques were developed when the electromechanical telephone switches and Private Branch Exchanges (PBX) were slowly being phased out by the digital telephone switches and to replace all the additional associated external signaling units for dedicated voice channels. 

http://en.wikipedia.org/wiki/Signalling_%28telecommunications%29

The digital switching technology also changed the real estate factor due to the size of the associated hardware. Once required tens of thousand of square foot to hold the hardware for a standard electromechanical switch can now be fitted into less than 25 percent of the original floor space.

http://en.wikipedia.org/wiki/Telephone_exchange

The analogue multiplexing equipment that once connects the old switches and the analogue transmission medium also got a digital facelift and liposuction.

http://en.wikipedia.org/wiki/Bandwidth_%28computing%29

Of course once the switches are digitized, the transmission medium and the network need to catch up with the rest of the digital technology.  The analogue radios and microwave towers with the old school HUGE channel banks and multiplexing equipment the size of the 16 wheeler box car were replaced by digital multiplex the size of a campus quad frig.  

http://en.wikipedia.org/wiki/DMS-100  (Nortel Digital Switch)

http://en.wikipedia.org/wiki/Virtual_private_network  (VPN)

Remember those Hippie fiber lamps in 70s? Who woulda thought that one day these optical fibers would be the backbones of optical technology that would go on to carry GOZILLION bits of data. Go figure. Oh yeah, them suckers are impervious to EMP, you know Electrode Magnetic Pulse, so the network would still be operating after a nuclear attack.  OMG, OMG, WORD? ...Like, Yeah! 

http://en.wikipedia.org/wiki/T-carrier (T1/E1 Carrier)

http://en.wikipedia.org/wiki/Optical_fiber  (Optical Fiber)

http://en.wikipedia.org/wiki/Wavelength-division_multiplexing  (DWDM)

http://en.wikipedia.org/wiki/Synchronous_optical_networking  SONET)

What is NOW in your iPhone would require the size of a Kenworth 18wheeler truck to contain back in late 1970s. The radio equipment for the Wi-Fi, the multiplexing hardware to support the 4G Network data transmission, the telecom switching and signaling processing and protocols, the GPS apps, etc, etc, etc….

I believe Cisco is taking the opportunity to market their goodies (See products and services at below link) in on this digital optical network.

http://en.wikipedia.org/wiki/Cisco_Systems